API 5500 2-channel Parametric Equalizer

A Classic API EQ Made for the Modern Studio!

The API 5500 dual equalizer puts the great sound and classic design of an API original into a rackmountable package that's even more versatile! Based on the venerable 550 equalizer designed by API founder Saul Walker, the 5500 adds new features such as a Range control for finer adjustments, true hard-wire bypass, and an integrated power supply that lets you apply mutes noiselessly. Two hand-built 2520 op amps (coupled with API's 2503 output transformer) provide plenty of headroom for clean operation. Whether you're tracking, mixing, or mastering, you'll love what the 5500 does for your sound. 

The legacy of a classic API equalizer

The 5500 manages to make a legendary EQ design more relevant and user-friendly than ever. The lineage of the 5500 circuit can be traced back to the original 550 equalizer designed by Saul Walker, the founder of Automated Processes Inc. The 550 was designed as a console equalizer which, due to the architecture of the recording console, uses an unbalanced input. Because the ergonomics of a console dictate that the controls take up little space, sometimes the number of included functions can be limited. The 5500 is specifically designed to address these limitations. It has a balanced input, a true straight-wire bypass, an integrated power supply with noiseless muting, and a range control that expands it versatility to mastering applications.

No ICs in the signal path, plenty of headroom

Like all API products, the 5500 contains no integrated circuits in its signal path. The gain comes from two hand-built 2520 operational amplifiers in each channel. The balanced input is handled by a 2510 discrete operational amplifier, which is similar to the 2520, but without the high current output stage. Besides being a key component of the API sound, the 2520 coupled with the API 2503 output transformer is capable of delivering +30dBm before clipping. With this much headroom, it is unlikely that the 5500 can be driven to distortion unless perhaps another API unit is driving the input!

A finer range of control

The Range control feature gives you a high degree of control over the 55OO. The range of the amplitude controls can be reduced to 1/2 or 1/4 of their stated scale, providing a means of adjusting the tonal balance with finer resolution in an even gentler manner. This should be especially useful for complex program material as contained in stems or submixes, and is ideally suited for mastering purposes.

True bypass means no signal loss and no "thumps"

You'll appreciate the 5500's true hardwire bypass. In this mode the output connector is wired directly to the input. Shortly after the power is first applied, or immediately after it is lost, a special circuit enables bypass mode so signal is never lost and power thumps are never heard.

API 5500 Dual EQ with Range Switch Features:

• Classic 550B equalizer design
• Two Range switches individually alter gain steps
• Useable as a 550B, 550D or 550M
• Peak/Shelf switch on HI and Lo bands
• True hardwire bypass
• Balanced in and out on XLR
• Unbalanced input on 1/4"
• EQ In/Out switch

 STL Pro Audio is an authorised reseller for API Audio.